Thank you!
I got your source code, re-build ,and run on my Gamebuino clone.
* filled
Flash screen, even if set max speed.
* Horizontal, Vertical stripes.
Moving stripes, in any speed. (that's like TV noise)
* Checkerd small
It's similer to default GRAY fill.
* Checkerd Learge
In high spped, it's still not looks Gray but looks like 'Tartan Check'.
* Grid
It's not looks Gray.
This is very nice effect, when something is power up state.
* Light Gray
It's not looks Gray.
That seem to shaking dots.
* Dark Gray
It's not looks Gray.
It's looks like default Gray pattern
* Composite
Any pattern is clearly different.
That's don't Gray what I expect, but that pattern is very useful to display multi-color graphics.
Conclusion.
OLED is very high response.
The way which is Blinking dots is not useful to represent Gray color.
Dither pattern is very suitable.
And some animated Dither pattern is good to represent special effect.
Thank you for your nice utility program!
(and sorry for my poor English.